public class MathUtil {
    public  static int add(int a,int b) {
        return a+b;
    }
    public  static int sub(int a,int b) {
        return a-b;
    }
    public static int mul (int a,int b) {
        return a * b;
    }
    public static int div (int a,int b) {
        return a / b;
    }
    public static int square(int a) {
        return a * a;
    }
    //平方根，同学6 wny的代码
    public static double sqrt(int a) {
        return Math.sqrt(a);
    }
    //减法，小棋棋的代码

}